The present application is a continuation of International Patent Application No. PCT/EP03/10840, filed on Sep. 27, 2003, and claims priority under 35 U.S.C. § 119 to German Application No. 102 53 936.7, filed Nov. 19, 2002. The entire disclosure of the aforementioned documents is herein expressly incorporated by reference.
The present invention relates to a procedure for preventing a motor vehicle from moving after the engine is turned off, as well as corresponding safety equipment for a motor vehicle.
In particular, the present invention involves the requirements resulting from the key interlock regulation under Federal Motor Vehicle Safety Standards (FMVSS) No. 114. This regulation states, among other things, that the ignition key must only be removable in motor vehicles with automatic transmissions if the gear-select lever of the automatic transmission is in the “P” for Park position. This is intended to prevent the driver from leaving the vehicle without having first made sure that the vehicle cannot accidentally move. In order to satisfy this regulation, the ignition switch can have suitable mechanical locking mechanisms which can be activated via the ignition key.
Increasingly, however, motor vehicle access systems and starting systems have no mechanical ignition. Such keyless mechanical starting systems with no mechanical ignition include an identification transducer (ID transducer) to be carried by the vehicle user, as well as a device for starting and stopping the engine. As soon as the ID transducer is identified inside the vehicle, it is authenticated through a question-and-answer dialog between the ID transducer and a transceiver unit, and positive authentification proving the ID transducer is authorized for use of the vehicle, enables the engine to be started after the starting device is activated.
The ID transducer can be designed as a key, but has no key bit and is only an “electronic” key. The ID transducer is introduced into a receptacle in the vehicle by the user just like a key before the vehicle is started. In order to meet the key interlock requirement cited above, measures are proposed to lock the ID transducer in the receptacle if the vehicle is not in the “P” for Park position.
The latest developments, however, no longer require the ID transducer to be introduced into the receptacle at all to start the engine. Instead, the electronics in the vehicle determine the presence of the ID transducer inside the vehicle, and perform the necessary authentification regardless of whether the ID transducer is in the receptacle. The corresponding new developments are known as “comfort access” or “keyless go”.
In the case of these new systems, the key interlock regulation can no longer be complied with by locking the ID transducer since the ID transducer no longer has to be in a corresponding receptacle for the vehicle to be driven. Other approaches are now required for a solution.
One approach consists of taking steps so that the driver cannot turn off the engine if the gear position “P” for Park is not engaged. This measure makes sure in fact that the driver will not normally leave his vehicle without having made sure that it cannot move, by engaging the gear position “P”. The key interlock regulation is thereby met.
This solution has the drawback, however, that the engine cannot be turned off even in certain danger situations or in situations which the driver thinks are dangerous, such as when, for example, problems occur with the engine while driving, the gas pedal sticks or the like.
The present invention is therefore directed to a solution for satisfying the key interlock regulation when keyless starting systems are used in which ID transducers can be located anywhere in the vehicle without a preset physical connection to other parts of the vehicle, and the driver can still turn off the engine in danger situations while driving.
According to the present invention it is possible to turn off the engine even while driving if the speed of the vehicle is greater than a certain threshold speed. Below the threshold speed, the vehicle must first be brought to a stop and Park position “P” must be engaged before the engine can be turned off. As a rule and with proper operation, the driver and ID transducer cannot leave a vehicle whose engine is turned off without first having engaged the Park position. This satisfies the key interlock regulation. In an emergency, however, the driver can also switch off the ignition while driving if the driver deems this necessary. If such an emergency occurs below the threshold speed, the driver can rapidly and safely brake the vehicle to a stop and then engage Park position “P” if necessary and turn off the engine.
The threshold speed should of course be high enough for there to be no fear of misusing the engine turn-off function in a moving vehicle. In accordance with exemplary embodiments of the present invention, the threshold speed can be approximately 15 kilometers per hour.
Another preferred embodiment of the present invention also allows the engine to be turned off regardless of the selected gear position and regardless of the threshold speed of the vehicle if the vehicle's own controls detect an engine problem. This measure is expedient and does not violate the key interlock regulation.